Legend:

<para>The domain name server to query. If the name of the check is in-addr.arpa, the system default nameserver is used. Otherwise, the nameserver is the %[target_ip] of the the check. If set to the string "default" the underlying system default nameserver is used.</para>

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</listitem>

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</varlistentry>

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</variablelist>

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<variablelist>

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<varlistentry>

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<term>port</term>

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<listitem>

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<variablelist>

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<varlistentry>

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<term>required</term>

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<listitem>

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<para>optional</para>

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</listitem>

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</varlistentry>

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<varlistentry>

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<term>default</term>

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<listitem>

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<para>53</para>

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</listitem>

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</varlistentry>

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<varlistentry>

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<term>allowed</term>

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<listitem>

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<para>\d+</para>

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</listitem>

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</varlistentry>

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</variablelist>

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<para>The port on which the remote server's DNS service is running.</para>